Safety foot control

ABSTRACT

A foot control such as a switch or valve of the treadle-operated type is provided with a guard cover inclosing the sides and top of the treadle and a movable abutment or stop normally retaining and locking the treadle in normal elevated unactuated position, the abutment or stop being disengageable by inward movement of a pivoted trip lever disposed at the inner end of the guard cover and treadle for actuation by the toe of the operator and being accessible only by insertion of the foot of the operator between the treadle and guard cover from the outer open end thereof. An additional safety measure may be the use of dual return springs for the treadle and stop.

United States Patent [1 1- Dibonaventura 'et al.

[ 1 3,759,115 1 Sept. 18, I973 SAFETY FOOT CONTROL [73] Assignee: TheLinemaster Switch Corporation, Woodstock, Conn.

[22] Filed: Apr. 19, 1972 [21] Appl. No.: 245,591

[52] U.S. C1... 74/512, 74/529 [51] Int. Cl G05g H14 [58] Field ofSearch 74/561, 565, 526, 74/512, 529; 192/3 T, 129 R, 129 A, 129 B;100/53 [56] References Cited UNITED STATES PATENTS 2,619,846 12/1952Wales ct a1. 74/512 2,693,716 11/1954 Ludwig 74/512 PrimaryExaminer-Charles J. Myhre Assistant Examiner-F. D. ShoemakerAttorney-John M. Prutzman et a1.

[57] ABSTRACT A foot control such as a switch or valve of thetreadleoperated type is provided with a guard cover inclosing the sidesand top of the treadle and a movable abutment or stop normally retainingand locking the treadle in normal elevated unactuated position, theabutment or stop being disengageable by inward movement of a pivotedtrip lever disposed at the inner end of the guard cover and treadle foractuation by the toe of the operator and being accessible only byinsertion of the foot of the operator between the treadle and guardcover from the outer open end thereof. An additional safety measure maybe the use of dual return springs for the treadle and stop.

8 Claims, 3 Drawing Figures SAFETY Foor CONTROL BACKGROUND AND SUMMARYOF THE INVENTION bending machines, and the like. Such controls arenormally placed on the floor or similar supporting surface for actuationby the foot of the operator, thus freeing the operators hands for otherfunctions.

Because of the usual locationof the control on the floor or the like itis very easily susceptible to being inadvertently stepped upon orimpinged upon by falling objects causing actuation of the treadle andunexpected operation of the machine being controlled. In some instancesthe control may be actuated merely by accidently bumping or kicking it,or if the control is dropped while being moved or relocated. Thiscreates a very dangerous situation and constitutes an intolerable safetyhazard.

Accordingly, it is an object of the invention to provide a foot controlof the treadle-operated type which is constructed to overcome thehazards referred to, namely, which is not susceptible to inadvertent oraccidental activation under normal conditions of use.

Another object is to provide a foot control of the type referred towhich in addition to being constructed for safe use, is so arranged thatnormal operation is not interfered with and the operator is not requiredto make any awkward or unusual movements in order to actuate thecontrol.

A further object is to provide a safety feature as described which isfully automatic in operation and requires no act of the operator tocause the safety feature to function. Included in this object is theprovision of a safety feature which is dependable in operation and willnot malfunction under normal conditions of use and which cannot bereadily rendered inoperable either purposely or inadvertently.

An additional object is to provide a safety device of the type referredto which is of rugged and durable construction so as to provide a longtroublefree service life, and-yet which can be applied to a foot controlat reasonable cost. I

Other objects will be in part obvious and in part pointed out in moredetail hereinafter.

A better understanding of the invention will be ob tained from thefollowing detailed description and accompanying drawings illustrating apreferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF A PREFERRED EMBODIMENTReferring to the drawings in detail, a foot control in which a preferredembodiment of the safety features of the present invention has beenincorporated is shown as comprising a base 10 preferably formed of castmetal having an upwardly opening compartment section 11 and a forwardlyextending ledge or platform 12. The base is provided with anti-skidrubber feet 13 which together with the weight of the control is normallysufficient to hold the control in desired position on the floor or othersupporting surface. However, openings 14 are also provided for thereception of screws or bolts or other fastening means by which the basemay be immovably anchored on a floor or supporting surface.

Within the compartment section 11 is a valve or switch shown somewhatdiagrammatically at 15 for connection to an associated machine or otherdevice to be controlled, the connection (not shown) being adapted to bemade through the rear access opening 16. Pivotally mounted on the base10 is an outwardly extending treadle 20 disposed above the ledge orplatform 12 and also preferably made of cast metal. The treadle 20 has atread portion 21 which is serrated on its upper surface, and twointegral side arms 22 which are secured by set screws 23 (one shown) tothe opposite ends of a shaft 24 which extends transversely through thecompartment section 11 and is joumaled in the side walls thereof. Eachside arm 22 has a projection 25 adapted to engage against a boss orshoulder 26 on the base 10 to function as a stop limiting upwardpivoting movement of the treadle 20.

Within the compartment section 11 and secured to shaft 24 for movementtherewith is an actuating arm 31 which is adapted to actuate the valveor switch I5 when the treadle is depressed. As will be obvious,depression of the treadle 20 causes turning movement of the shaft 24 andcorresponding pivoting movement of the actuating arm 31.

The treadle is urged to the raised position shown in FIGS. 1 and 2, andas limited by the stops 25, by a spring 32 which is held in capturedposition by being seated on the circular boss 33 formed in the ledge orplatform 12 and having its upper end received in a circular recess 34 onthe underside of the tread portion 21 of the treadle 20. A second returnspring 35 is provided within the compartment section 11 being seated atits lower end in a recess 36 and engaged at its upper end against alever 37 secured to shaft 24 by screw 38. In the preferred embodimentboth spring 32 and spring 35 are designed to have sufficient force toreturn the treadle to the unactuated position shown in FIGS. 1 and 2 sothat even though one of these springs should break or otherwise fail,the mechanism will return to the unactuated position and will stillcontinue to operate until a suitable repair or replacement can be made.

The cover of the control is a metal casting 40 having a rear coverportion 41' configured to fit over and close the compartment section11.,A gasket 39 is disposed between the compartment section 11 and coverportion 41 which is secured thereto by screws 42. Extending forwardlyfrom the rear cover portion 41 is an enlarged guard cover portion 43 inthe form of a cowl which completely incloses the side edges and'top ofthe treadle 20 providing access to the treadle only through the endopening 44.

In accordance with the invention, a stop is provided which normallyholds and locks the treadle in its raised unactuated position. In-thepreferred embodiment the stop comprises a pair of hardened steel bars 50each being independently mounted on the lower end for pivoting movementon a rod 51 which extends through and is supported by ribs 52 formed onthe upper surface of the ledge or platform 12. A cylindrical separator53 on the rod 51 between bars 50 maintains the bars 50 in spaced apartposition adjacent the ribs 52. The bars 50 are dimensioned so that whenthe bars are in upright position, the upper surfaces 54 thereof will fitunder and engage the rear edge portion of the tread section 21 when thetreadle 20 is in fully raised position. The treadle 20 which, aspreviously mentioned, is preferably formed of cast metal, is alsopreferably hardened in the area which is engaged by the bars 50 toprevent wear. Each bar has an inverted L-shaped upper extension 55 whichis engaged by a coil spring 56 urging the bars 50 to the holding orlocking position shown in FIGS. 1 and 2. The upper extensions 55 alsobear against a trip plate 60 formed of sheet metal with edge extensions61 bent inwardly to form downwardly depending arms which are pivotallymounted on the opposite ends of rod 51. The trip plate 60 by reason ofbeing engaged by the extensions 55 on the bars 50 which in turn areurged to locking position by the springs 56, is thereby also urged tothe forward position shown in FIGSJ and 2. Forward movement is limitedby engagement of arms 61 with the rear edge of the tread section 21 ofthe treadle 20. The upper portion 62 of the trip plate 60 is forwardlyinclined both for clearance purposes and for facilitating engagementtherewith by the toe of the operator's foot.

The operation of the control and safety features will be apparent fromthe foregoing description in connection with the following explanation.When the parts are in the normal locked position as shown in FIGS. 1 and2 of the drawing, the treadle cannot be depressed because of theengagement of the bars 50 underneath the edge of the tread portion 21blocking any downward movement of the treadle. However, if the tripplate 60 is thrust rearwardly or inwardly, then the bars 50 are moved orpivoted rearwardly to the inclined position disengaging the treadle 20so that it may be depressed to actuated position as shown in FIG. 3 ofthe drawing.

The full inclosure of the treadle by the cowl shaped guard cover 43except for the end opening 44 will normally protect the control againstactuation such as by a directly falling object, but this is notsufficient in the event the exposed end of the treadle is engaged or thecontrol is subjected to a sudden jar or shock. However, by reason of theadditional safety features of the inven tion, the control cannot beactuated even though the exposed end of the treadle is struckinadvertently such as by being engaged by a heel or toe or it subjectedto shock because of the locking action of the bars 50. In order toactuate the control, the operator has to perform two related movementswhich are, first, to thrust his foot under the cowl shaped cover abovethe treadle portion 21 and press inwardly on the trip plate 60 torelease the bars 50 from looking position and, second, while holding thetrip plate 60 in releasing position, pressing downwardly on the treadletojpivot the same and actuate the switch or valve. These are easy andsimple movements for the operator to perform causing substantiallyimpossible to cause them to be actuated inadvertently or for theoperator to inadvertently or deliberately render the safety featuresinoperable, thus insuring full portection aginst accidental tripping orac tuation of the control.

As will be apparent to persons skilled in the art, variousmodifications, adaptations and variations of the foregoing specificdisclosure can be made without departing from the teachings of thepresent invention.

We claim:

1. In a foot control of the type having a base and a treadle mounted onthe base for movement between a raised and a depressed position, a guardcover extending over the treadle, a retractable stop normally engagingunder the treadle to prevent depression of the treadle, and a movabletrip plate at the inner end of the treadle engageable by the toe of theoperators foot when placed between the treadle and guard cover, the tripplate being operatively connected to the stop to remove the stop frombeneath the treadle when the trip plate is moved inwardly by the toe ofthe operator.

2. In a foot control as set forth in claim 1 wherein the treadle ispivotally mounted on the base and the guard cover is in the form of acowl inclosing the sides and top of the treadle and permitting access tothe treadle only from the outer end thereof.

3. In a foot control as set forth in claim 2 wherein the stop is a barpivotally mounted at one end on the base for pivoting movement betweenan upright position engaging under the treadle to prevent depressionthereof and an inclined position permitting the treadle to be depressed.

4. In a foot control as set forth in claim 2 wherein the stop comprisesa pair of bars independently mounted on the base for pivoting movementbetween an upright position engaging under the treadle to preventdepression thereof and a retracted position disengaging the treadle topermit depression thereof, and a separate spring for each bar urging itto said upright position.

5. In a foot control as set forth in claim 2 wherein the stop comprisesat least one bar pivotally mounted on the base for'movement between aposition engaging underneath a rear edge of the treadle to preventdepression of the treadle, and a rearwardly retracted positiondisengaging the treadle to permit depression thereof, the trip plate ispivotally mounted on the base for extension upwardly adjacent the saidrear edge of the treadle, and the bar is provided with a projectionengaging the rear surface of the trip plate to cause the bar to bepivoted to retracted-position when the trip plate is moved rearwardly ofthe treadle.

6. In a foot control as set forth in claim 5 wherein the treadle isformed of metal which is hardened in the area engaged by the bar stop.

7. In a foot control as set forth in claim 5 wherein a pair of separatereturn springs are operatively connected to the treadle for biasing thetreadle in an upward direction, each of said springs being of sufficientforce to move the treadle to fully raised position independently of theforce of the other spring.

8. In a foot control as set forth in claim 2 wherein the trip plate ispivotally mounted on the base and extends upwardly at the rear of thetreadle, and the stop comprises at least one bar pivotally mounted onthe base for movement between an upright position engaging under thetreadle to prevent depression thereof and a rearwardly pivoted positionreleasing the treadle for de' pression thereof, a portion of the barbeing engaged behind the trip plate to cause the bar to be pivoted totreadle releasing position when the trip plate is pivoted rearwardlyrelative to the treadle.

* K 1B i

1. In a foot control of the type having a base and a treadle mounted onthe base for movement between a raised and a depressed position, a guardcover extending over the treadle, a retractable stop normally engagingunder the treadle to prevent depression of the treadle, and a movabletrip plate at the inner end of the treadle engageable by the toe of theoperator''s foot when placed between the treadle and guard cover, thetrip plate being operatively connected to the stop to remove the stopfrom beneath the treadle when the trip plate is moved inwardly by thetoe of the operator.
 2. In a foot control as set forth in claim 1wherein the treadle is pivotally mounted on the base and the guard coveris in the form of a cowl inclosing the sides and top of the treadle andpermitting access to the treadle only from the outer end thereof.
 3. Ina foot control as set forth in claim 2 wherein the stop is a barpivotally mounted at one end on the base for pivoting movement betweenan upright position engaging under the treadle to prevent depressionthereof and an inclined position permitting the treadle to be depressed.4. In a foot control as set forth in claim 2 wherein the stop comprisesa pair of bars independently mounted on the base for pivoting movementbetween an upright position engaging under the treadle to preventdepression thereof and a retracted position disengaging the treadle topermit depression thereof, and a separate spring for each bar urging itto said upright position.
 5. In a foot control as set forth in claim 2wherein the stop comprises at least one bar pivotally mounted on thebase for movement between a position engaging underneath a rear edge ofthe treadle to prevent depression of the treadle, and a rearwardlyretracted position disengaging the treadle to permit depression thereof,the trip plate is pivotally mounted on the base for extension upwardlyadjacent the said rear edge of the treadle, and the bar is provided witha projection engaging the rear surface of the trip plate to cause thebar to be pivoted to retracted position when the trip plate is movedrearwardly of the treadle.
 6. In a foot control as set forth in claim 5wherein the treadle is formed of metal which is hardened in the areaengaged by the bar stop.
 7. In a foot control as set forth in claim 5wherein a pair of separate return springs are operatively connected tothe treadle for biasing the treadle in an upward direction, each of saidsprings being of sufficient force to move the treadle to fully raisedposition independently of the force of the other spring.
 8. In a footcontrol as set forth in claim 2 wherein the trip plate is pivotallymounted on the base and extends upwardly at the rear of the treadle, andthe stop comprises at least one bar pivotally mounted on the base formovement between an upright position engaging under the treadle toprevent depression thereof and a rearwardly pivoted position releasingthe treadle for depression thereof, a portion of the bar being engagedbehind the trip plate to cause the bar to be pivoted to treadlereleasing position when the trip plate is pivoted rearwardly relative tothe treadle.